1. Technical Field
The present disclosure relates to a three-dimensional image processing apparatus which processes a three-dimensional image (three-dimensional stereoscopic image).
2. Related Art
Conventionally, display devices which can present the user with an image for a left eye and an image for a right eye with a parallax to provide a three-dimensional effect for the user (hereinafter, referred to as “three-dimensional image display devices”) have been known. The three-dimensional image display devices can provide a three-dimensional effect for the user by showing the left eye and the right eye an image for the left eye and an image for the right eye independently. Conventionally, image capturing apparatuses which can capture a three-dimensional image composed of the image for a left eye and the image for a right eye with a parallax (hereinafter, referred to as “three-dimensional image capturing apparatuses”) have also been known.
A three-dimensional image (an image for a left eye and an image for a right eye) which is generated by photographing an image with a large parallax of the background (subject in the background) or the foreground (subject in the foreground) may exceed the fusion limit for a human stereovision, which may be an image hard for the user to perform stereovision or an image causing the user to feel fatigue. In order to avoid generation of a three-dimensional image unfavorable for the user, there is a technique for obtaining a good three-dimensional image by performing parallax adjustment or stereo base adjustment.
The parallax adjustment is a technique mainly used when the background (subject in the background) exceeds the fusion limit. By performing the parallax adjustment to non-linearly compress the distance to the background (subject in the background), the background (subject in the background) which was hard to recognize in stereovision is brought closer, and therefore, a three-dimensional image which is easy for the user to perform stereovision can be generated.
The stereo base adjustment is a technique for adjusting the three-dimensional effect by adjusting the distance between the camera for capturing an image for a left eye and the camera for capturing an image for a right eye (stereo base (base length)). By performing the stereo base adjustment, the dynamic range of the parallax can be made smaller. Therefore, by performing appropriate stereo base adjustment before image capturing, a three-dimensional image can be generated so that entirely from the foreground (subject in the foreground) to the background (subject in the background) is contained in the fusional area.
Further, when a three-dimensional image is displayed in a small-sized display device, the parallax of the three-dimensional image (an image for a left eye and an image for a right eye) becomes smaller, and accordingly, the background is compressed. Therefore, in that case, the three-dimensional image displayed in the small-sized display device is easily recognized.
Making full use of the above described techniques (parallax adjustment and stereo base adjustment) in capturing a three-dimensional image enables capturing of a three-dimensional image which can be easily viewed as a three-dimensional image when a three-dimensional display is performed in a predetermined display environment. For example, in JP 3157384 B1, reducing the parallax from the original value to bring the subject in the fusional area of the stereovision in capturing a three-dimensional image enables capturing of a three-dimensional image which can be easily viewed as a three-dimensional image.